* Velocity is the rate of change of an object's position. If an object is stationary, its velocity is zero.
* Acceleration is the rate of change of an object's *velocity*.
Think about these scenarios:
* A ball at the top of its trajectory: Just before a ball thrown upwards starts to fall back down, it momentarily has zero velocity (it's stopped for a split second). However, it's still accelerating due to gravity, which is pulling it downwards.
* A car at a red light: A car stopped at a red light has zero velocity. But when the light turns green, the car accelerates, meaning its velocity starts to increase even though it was initially at rest.
In summary: An object can be at rest (zero velocity) and still be accelerating if a force is acting on it, causing its velocity to change.
